BillGuard, which is still in private beta, aims to alert users of unwanted charges such as hidden fees, billing errors, scams and fraud on credit card bills. BillGuard essentially crowdsources scams by alerting you when a charge on your bill is flagged by anyone else using BillGuard. The startup will also take into account its own analysis and monitor the web for any complaints about credit card scams.

Here’s how it works. The startup’s proprietary algorithm aggregates, mines, normalizes data from its own reports and from users. BillGuard will then scan your card activity daily, and email you when your attention is required.

While many credit card companies have fraud protection services, it’s up to the consumer to be vigilant about any billing errors or hidden fees on credit card bills. And if BillGuard ends up building a large user base, its crowdsourced information could be particularly useful.